In recent years, such AV devices connected to a display as an HDD recorder, a DVD player, a set-top box and an AV amplifier are increasingly made commercially available, as a result of which the connection for an image or audio between different devices are increasingly complicated. In order to solve the foregoing problem, electronic devices provided with a radio communication function which eliminate the need for any physical connection by users are increasing. However, the radio communication has unfavorably led to the failure of the communication resulting from the interference of electromagnetic waves as the radio communication is more often performed. In order to unfailingly perform the radio communication in an AV rack, there is a conventional technology for improving an accuracy in the communication of a remote control signal in the AV rack as recited in the Patent Document 1.
In the conventional technology, an optical function layer characterized as follows is provided at a front door:                light in a visible range is transmitted therethrough both outside and inside;        a signal in an infrared range from inside is reflected thereon; and        a signal in the infrared range from outside is absorbed therein.            Patent Document 1: H07-193877 of the Japanese Patent Applications Laid-Open